Bearing sleeve

ABSTRACT

Disclosed is a bearing sleeve for supporting a shaft of an air cycle machine. The bearing sleeve includes an outer diameter and an inner diameter. The outer diameter is within a range of 3.222 and 3.224 inches. Further included is a foil retaining cavity provided in the inner diameter of the sleeve. The foil retaining cavity includes a slot and first and second openings located at opposing axial ends of the slot. Each of the first and second openings include a small portion and a large portion having different axial lengths. A ratio of the combined axial lengths of the large portions to an axial length of the foil retaining cavity is within a range of 0.19:1 and 0.22:1.

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/788,328, filed Mar. 15, 2013, the entirety of which is hereinincorporated by reference.

BACKGROUND

This application relates to bearing sleeves, and in particular tobearing sleeves for air cycle machines (ACMs).

ACMs are known and include a compressor which compresses air anddelivers the air for a downstream use, such as is an aircraft air supplysystem. A portion of the air from the compressor outlet passes over aturbine rotor, driving the turbine rotor to rotate. An ACM may includeseveral rotating shafts supported by air bearings. One known type of airbearing includes a foil assembly supported by a bearing sleeve.

SUMMARY

In one exemplary embodiment of this disclosure includes a bearing sleeveconfigured for supporting a shaft of an air cycle machine. The bearingsleeve includes an outer diameter and an inner diameter. The outerdiameter is within a range of 3.222 and 3.224 inches. Further includedis a foil retaining cavity provided in the inner diameter of the sleeve.The foil retaining cavity includes a slot and first and second openingslocated at opposing axial ends of the slot. Each of the first and secondopenings include a small portion and a large portion having differentaxial lengths. A ratio of the combined axial lengths of the largeportions to an axial length of the foil retaining cavity is within arange of 0.19:1 and 0.22:1.

In a further embodiment of any of the above, a ratio of the outerdiameter to the inner diameter is within a range of 1.143:1 and 1.144:1.

In a further embodiment of any of the above, the large portions of thefirst and second openings each have axial lengths within a range of0.265 and 0.305 inches.

In a further embodiment of any of the above, the small portions of thefirst and second openings each have axial lengths within a range of 0.12and 0.16 inches.

In a further embodiment of any of the above, the large portions of thefirst and second openings each have widths within a range of 0.215 and0.225 inches, measured relative to a centerline of the slot.

In a further embodiment of any of the above, the small portions of thefirst and second openings each have widths within a range of 0.065 and0.075 inches, measured relative to a centerline of the slot.

In a further embodiment of any of the above, the foil retaining cavityhas a length within a range of 2.795 and 2.805 inches.

In a further embodiment of any of the above, the bearing sleeve has anoverall axial length within a range of 3.33 and 3.35 inches.

In a further embodiment of any of the above, the slot has a width withina range of 0.041 and 0.047 inches.

Another exemplary embodiment of this disclosure includes an air cyclemachine having a bearing sleeve. The bearing sleeve includes an outerdiameter and an inner diameter. The outer diameter is within a range of3.222 and 3.224 inches. Further included is a foil retaining cavityprovided in the inner diameter of the sleeve. The foil retaining cavityincludes a slot and first and second openings located at opposing axialends of the slot. Each of the first and second openings include a smallportion and a large portion having different axial lengths. A ratio ofthe combined axial lengths of the large portions to an axial length ofthe foil retaining cavity is within a range of 0.19:1 and 0.22:1.

In a further embodiment of any of the above, the air cycle machineincludes a foil assembly, the foil assembly including a bent portion andtabs at axial ends thereof.

In a further embodiment of any of the above, the bent portion isreceived within the slot, and wherein the tabs are received within thelarge portions of the first and second openings.

In a further embodiment of any of the above, the air cycle machineincludes at least one O-ring supporting the bearing sleeve within acentral opening in the air cycle machine, the O-ring directly engagedwith the outer diameter of the bearing sleeve.

In a further embodiment of any of the above, a ratio of the outerdiameter to the inner diameter is within a range of 1.143:1 and 1.145:1.

In a further embodiment of any of the above, the large portions of thefirst and second openings each have axial lengths within a range of0.265 and 0.305 inches.

In a further embodiment of any of the above, the small portions of thefirst and second openings each have axial lengths within a range of 0.12and 0.16 inches.

In a further embodiment of any of the above, the large portions of thefirst and second openings each have widths within a range of 0.215 and0.225 inches, measured relative to a centerline of the slot.

In a further embodiment of any of the above, the small portions of thefirst and second openings each have widths within a range of 0.065 and0.075 inches, measured relative to a centerline of the slot.

In a further embodiment of any of the above, the foil retaining cavityhas a length within a range of 2.795 and 2.805 inches.

In a further embodiment of any of the above, the bearing sleeve has anoverall axial length within a range of 3.33 and 3.35 inches.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings can be briefly described as follows:

FIG. 1 schematically illustrates an example air cycle machine (ACM).

FIG. 2 illustrates a cross-sectional view of an example bearing sleeve.

FIG. 3 is a view taken along line A-A from FIG. 2.

FIG. 4 is a view taken along line B-B from FIG. 3.

DETAILED DESCRIPTION

FIG. 1 schematically illustrates an air cycle machine (ACM) 10 includinga fan, or compressor, section 12, a turbine section 14, and at least oneshaft 16. The shaft 16 is supported by a bearing assembly 18, whichincludes a bearing sleeve 20, a foil assembly 22, and O-rings 24. Thefoil assembly 22 is positioned circumferentially within the bearingsleeve 20. The foil assembly 22 is configured to interact with the shaft16 and allow the shaft 16 to rotate, as is known in the art. The bearingsleeve 20 is supported within a central opening in the ACM 10 by way ofthe O-rings 24.

FIG. 2 illustrates a cross-sectional view of an example bearing sleeve20. The example bearing sleeve 20, in one example, is positionedadjacent the fan section 12 of the ACM 10. The bearing sleeve 20includes an outer diameter D1, an inner diameter D2, and spans an axiallength L1. The foil assembly 22 is supported by the bearing sleeve 20 byway of a foil retaining cavity F provided in the inner diameter of thebearing sleeve 20. In the example, the axial length L1 of the bearingsleeve 20 is within a range of 3.33 and 3.35 inches (approximately 8.458to 8.509 cm). Further, the foil retaining cavity has an overall lengthL2 within a range of 2.795 and 2.805 inches (approximately 7.099 to7.125 cm).

The outer diameter D1 of the bearing sleeve 20 is selected to provide adesired preload relative to the O-rings 24. This preload is selectedsuch that the bearing sleeve 20 will remain in place during operation,as well as to provide a desired damping level for the ACM 10. Forexample, the higher the preload, the higher the damping during operationof the ACM 10.

In one example, the outer diameter D1 is within a range of 3.222 and3.224 inches (approximately 8.184 to 8.188 cm). This D1 provides the ACMwith a relatively high level of damping while ensuring that the bearingsleeve 20 remains in place during operation. In this example, the ratioof the outer diameter D1 to the inner diameter D2 is within a range of1.143:1 and 1.145:1.

As illustrated in FIG. 3, which is a view taken along line A-A in FIG.2, the foil retaining cavity F includes a slot 26 and first and secondopenings 28, 30 at opposed axial ends of the slot 26. In one example theopenings 28, 30 each include large portion A, as well as a relativelysmaller portion B. The large portions A have an axial length L3, and thesmaller portions B have a smaller axial length L4.

In this example each large portion A has an axial length L3 of within arange of 0.265 and 0.305 inches (approximately 0.673 to 0.775 cm), whichis selected to correspond to a length of the tabs 34 of a foil assembly22 (FIG. 4). The length of the smaller portions L4 is within a range of0.12 and 0.16 inches (approximately 0.305 to 0.406 cm).

In this example, a ratio of the combined axial length of the largeportions L3 (e.g., 2×L3) to an overall axial length of the foilretaining cavity L2 is within a range of 0.19:1 and 0.22:1. This ratiorelates the length of the foil retaining cavity F used to interact withthe tabs of the foil assembly 22 (e.g., 2×L3) versus the overall lengthof the foil retaining cavity L2. While this is just one example, many ofthe dimensions disclosed herein are interrelated and thus can beusefully expressed in terms of ratios.

FIG. 4 is a view taken along line B-B from FIG. 3, and illustrates themanner in which the foil assembly 22 is retained by the foil cavity F.The foil assembly 22 includes a bent portion 32 along its length forreceipt into the slot 26. The slot 26 has a width W1 to receive the bentportion. In one example the width W1 is within a range of 0.041 and0.047 inches (approximately 0.104 to 0.120 cm). The slot 26 furtherincludes radii 26R at the base thereof, and break edges 26B where theslot 26 is provided into the inner diameter of the bearing sleeve 20 forease of machining.

The foil assembly 22 further includes tabs 34 at each axial end thereof.The tabs 34 are configured to be received within the large portions A ofthe first and second openings 28, 30 of the foil retaining cavity. Thetabs 34 have an axial length corresponding to the axial length L3 of thelarge portions A.

FIG. 4 further illustrates the widths of the large and small portions A,B of the openings 28, 30. In this example, large portion A has a widthW2 within a range of 0.215 and 0.225 inches (approximately 0.546 to0.575 cm), and small portion B has a width W3 within a range of 0.065and 0.075 inches (approximately 0.165 to 0.191 cm), with W2 and W3 eachmeasured relative to the centerline of the slot 26.

In one example, the bearing sleeve 20 is made of steel by way of anelectron discharge machining (EDM) process. The foil retaining cavity Fis formed during the EDM process in the example. After forming the foilretaining cavity F using the EDM process, the inner diameter D2 isfurther machined to provide a desired preload on the foil assembly 22.That is, the dimension of the inner diameter D2 is selected such thatthe foil assembly 22 engages the shaft 16 with an appropriate amount offorce such that the foil assembly 22 will remain in place duringoperation, while still permitting the shaft 16 to freely rotate.Machining the inner diameter after the EDM process has the benefits ofremoving any residue (e.g., burrs) left behind after the EDM process,and preventing any warping of the bearing sleeve 20.

This disclosure provides bearing sleeves that interact with a foilassembly, as well as O-rings, to provide appropriate preloads, whichrelate to the damping of the ACM and the support of the foil assembly,among other benefits.

Although the different examples have the specific components shown inthe illustrations, embodiments of this disclosure are not limited tothose particular combinations. It is possible to use some of thecomponents or features from one of the examples in combination withfeatures or components from another one of the examples.

One of ordinary skill in this art would understand that theabove-described embodiments are exemplary and non-limiting. That is,modifications of this disclosure would come within the scope of theclaims. Accordingly, the following claims should be studied to determinetheir true scope and content.

What is claimed is:
 1. A bearing sleeve for supporting a shaft of an aircycle machine, comprising: an outer diameter and an inner diameter,wherein the outer diameter is within a range of 3.222 and 3.224 inches;and a foil retaining cavity provided in the inner diameter, the foilretaining cavity including a slot and first and second openings locatedat opposing axial ends of the slot, each of the first and secondopenings including a small portion and a large portion having differentaxial lengths, wherein a ratio of the combined axial lengths of thelarge portions to an overall axial length of the foil retaining cavityis within a range of 0.19:1 and 0.22:1.
 2. The bearing sleeve as recitedin claim 1, wherein a ratio of the outer diameter to the inner diameteris within a range of 1.143:1 and 1.145:1.
 3. The bearing sleeve asrecited in claim 1, wherein the large portions of the first and secondopenings each have axial lengths within a range of 0.265 and 0.305inches.
 4. The bearing sleeve as recited in claim 1, wherein the smallportions of the first and second openings each have axial lengths withina range of 0.12 and 0.16 inches.
 5. The bearing sleeve as recited inclaim 1, wherein the large portions of the first and second openingseach have widths within a range of 0.215 and 0.225 inches, measuredrelative to a centerline of the slot.
 6. The bearing sleeve as recitedin claim 1, wherein the small portions of the first and second openingseach have widths within a range of 0.065 and 0.075 inches, measuredrelative to a centerline of the slot.
 7. The bearing sleeve as recitedin claim 1, wherein the foil retaining cavity has a length within arange of 2.795 and 2.805 inches.
 8. The bearing sleeve as recited inclaim 1, wherein the bearing sleeve has an overall axial length within arange of 3.33 and 3.35 inches.
 9. The bearing sleeve as recited in claim1, wherein the slot has a width width within a range of 0.041 and 0.047inches.
 10. An air cycle machine, comprising: a bearing sleeve, thebearing sleeve including an outer diameter and an inner diameter,wherein the outer diameter is within a range of 3.222 and 3.224 inches,the bearing sleeve further including a foil retaining cavity provided inthe inner diameter, the foil retaining cavity including a slot and firstand second openings located at opposing axial ends of the slot, each ofthe first and second openings including a small portion and a largeportion having different axial lengths, wherein a ratio of the combinedaxial lengths of the large portions to an overall axial length of thefoil retaining cavity is within a range of 0.19:1 and 0.22:1.
 11. Theair cycle machine as recited in claim 10, including a foil assembly, thefoil assembly including a bent portion and tabs at axial ends thereof.12. The air cycle machine as recited in claim 11, wherein the bentportion is received within the slot, and wherein the tabs are receivedwithin the large portions of the first and second openings.
 13. The aircycle machine as recited in claim 10, including at least one O-ringsupporting the bearing sleeve within a central opening in the air cyclemachine, the O-ring directly engaged with the outer diameter of thebearing sleeve.
 14. The air cycle machine as recited in claim 10,wherein a ratio of the outer diameter to the inner diameter is within arange of 1.143:1 and 1.145:1.
 15. The air cycle machine as recited inclaim 10, wherein the large portions of the first and second openingseach have axial lengths within a range of 0.265 and 0.305 inches. 16.The air cycle machine as recited in claim 10, wherein the small portionsof the first and second openings each have axial lengths within a rangeof 0.12 and 0.16 inches.
 17. The air cycle machine as recited in claim10, wherein the large portions of the first and second openings eachhave widths within a range of 0.215 and 0.225 inches, measured relativeto a centerline of the slot.
 18. The air cycle machine as recited inclaim 10, wherein the small portions of the first and second openingseach have widths within a range of 0.065 and 0.075 inches, measuredrelative to a centerline of the slot.
 19. The air cycle machine asrecited in claim 10, wherein the foil retaining cavity has a lengthwithin a range of 2.795 and 2.805 inches.
 20. The air cycle machine asrecited in claim 10, wherein the bearing sleeve has an overall axiallength within a range of 3.33 and 3.35 inches.